Digirig and HF Return in VHF SSB mode on TS2000

1

Hello,

I’m contacting you to see if you’ve noticed any problems with HF returns in VHF SSB.
I connected the Digirig with the Kenwood TS2000 connection cables, and at low power in FT8 with WSJT-X (5W), there are no problems.
However, when I increase the power (10, 20, 30, or 40W), the power is unstable, just like with HF returns.
The Big Wheel antenna I’m using is 25m from the transceiver with a SWR of 1.05.
I also noticed that the decoding level was low (20-30% max), even though the audio settings on the TS2000 and PC (microphone) were set to maximum.

Thanks, 73

Thierry

2

I do not have your radio, nor run VHF SSB, but I do not want your question to go too long without a response.

With VHF FM, indeed, I needed to put an RF ferrite bead on the USB cable from the Digirig to the computer to eliminate RF interference (RFI) for digital modes.

73 Constrainted

3

Hello Constrainted
Thanks for your advice,I’ll try a USB cable equipped with ferrites.
I’ll come back and let you know.
73, Thierry

4

That is one way. The way that I do it is with a clip-on-ferrite bead like this:

Amazon.com: Clip-on Noise Filter,VSKEY [10pcs 3mm] Anti-Interference High-Frequency Ferrite Core Choke Clip for Telephones,Tvs,Speakers,Radio,Audio Equipment Noise Suppressor (3mm Inner Diameter) : Electronics

but rather than Amazon, I buy from Mouser or Digikey (I am in US) which are more likely to have the proper ferrite mix for wideband RF suppression. This way, I can use my regular USB cables or borrow a cable when something goes wrong in the field.

73 Constrainted

5

I have this Constrainted…

6

OK. Name-brand TDK should be good, of course. Good luck! Please let us know your result.

73 Constrainted

7

The problem is identical with the news ferrite

I performed two tests.

The first was to go into the software menu and switch from an RTS command to a CAT command.
I then removed the 13-pin connector (audio in/out and TX command).
I switched to TX mode via WSJTX and noticed that there was no longer a feedback problem, which shows that the RS232 part isn’t causing a problem.

The second test was to put the RTS command back on the software and switch to TX with the audio level at its lowest.
Without audio input and increasing the power from 5, 10, 15, 20, and 25, I still get RF feedback even without audio input.
The feedback problem also occurs in AM and SSB, but there is no problem in FM or FSK.

This tests is make with dummy load

8

Hello,

I decided to revert to my old interface, which was equipped with a two 600/600 ohms transformer, a miniature USB sound card (mic and line) and a USB to RS232 converter for CAT management.

And now, without any problems, everything works.
Did the manufacturer actually test its solutions on a TS2000 ?
I think this is a good question to ask…

I also noticed that the rs232 / usb conversion of the Digirig interface had a tendency to produce low level noise, but noise was present on the audio output… (CEM problem in the design of the interface ?)

Thanks again Constrained